[100910] in North American Network Operators' Group
Re: unwise filtering policy from cox.net
daemon@ATHENA.MIT.EDU (Paul Jakma)
Wed Nov 21 16:10:54 2007
Date: Wed, 21 Nov 2007 21:06:55 +0000 (GMT)
From: Paul Jakma <paul@clubi.ie>
To: Sean Donelan <sean@donelan.com>
cc: "'nanog@merit.edu'" <nanog@merit.edu>
In-Reply-To: <Pine.GSO.4.64.0711210100050.27540@clifden.donelan.com>
Mail-Copies-To: paul@jakma.org
Mail-Followup-To: paul@jakma.org
Errors-To: owner-nanog@merit.edu
On Wed, 21 Nov 2007, Sean Donelan wrote:
>
> On Tue, 20 Nov 2007, goemon@anime.net wrote:
>> <abuse@cox.net>
>> (reason: 552 5.2.0 F77u1Y00B2ccxfT0000000 Message Refused. A URL in the
>> content of your message was found on...uribl.com. For resolution do not
>> contact Cox Communications, contact the block list administrators.)
>
> An unfortunate limitation of the SMTP protocol is it initially only
> looks at the right-hand side of an address when connecting to a
> server to send e-mail, and not the left-hand side.
> full) or the normal server administrators may make changes which
> affects all addresses passing through that server (i.e. block by IP
> address).
I guess you're saying there's something architectural in email that
makes it impossible/difficult (limitation) to apply different policy
to the LHS.
That's not correct though. The receiving MTA is quite free to apply
differing policies to different LHSes. And at least one MTA allows
you special-case measures applied to tables of addresses, such as
whether DNSbl lookups should be applied.
SMTP is distributed, so you do of course have to take care to keep
distributed policy consistent. But, again, that has nowt to do with
LHS/RHS of email addresses.
regards,
--
Paul Jakma paul@clubi.ie paul@jakma.org Key ID: 64A2FF6A
Fortune:
A plumber is needed, the network drain is clogged
